A network storage system typically provides multiple user devices access to one or more storage devices for recording and retrieving digital information. The storage system may be implemented according to a storage area network (SAN) architecture in one example. In a SAN, the storage system provides a remote host with block-level access to data stored in an array of interconnected mass storage devices, e.g., hard disk drives (HDDs). A network storage system may also include Network Attached Storage (NAS) or other appropriate architectures. Conventional HDDs use Perpendicular Magnetic Recording (PMR) technology to record data on non-overlapping parallel magnetic tracks. However, there are difficulties with scaling PMR drive capacity due to physical limitations inherent in the current recording process.
Shingled Magnetic Recording (SMR) is a new hard drive technology that was developed to overcome the scalability issues associated with PMR drives. SMR technology uses partially overlapping magnetic tracks that are layered on top of one another similar to roof shingles on a house. By increasing the platter density or tracks per inch (TPI) in this way, SMR technology allows a drive's storage capacity to be increased without increasing its physical size. Due to the track layout within an SMR drive, data is typically written sequentially in order to prevent the drive's write head from writing over previously recorded data on overlapping tracks.
The operating systems of existing storage systems and host devices generally are not restricted to writing data sequentially to hard drives. Consequently, changes may have to be made in the SMR drive firmware, host software, or both to manage non-sequential or random writes to the SMR drives in a storage system. However, the use of conventional SMR data management techniques may cause hardware compatibility issues and unpredictable system performance.